1. Field of the Invention
The present invention relates to a method of forming a flux layer on an aluminum plate member, a flux composition to be used in the forming method, and an aluminum plate member on which a flux layer was formed. The present invention is effective, in particular, for applying it to form the flux layer on the plate member constituting a heat exchanger made of aluminum.
2. Description of the Related Art
Conventional methods include a method of forming a flux layer for brazing on a surface of an aluminum alloy work disclosed in Japanese unexamined patent publication No. 2002-66731. In the forming method, a liquid containing a flux and a binder is spray-coated on a heated work, and then a flux layer is formed on a surface of the work after a drying step of drying with heat.
Although a step of heating the work is employed before spray-coating the liquid in the conventional method of forming the flux layer for brazing, a heat-drying step of heating and drying the work is necessary after the spray-coating step. Therefore, the conventional method has problems of taking long time for processing the work, as well as making steps complicated and upsizing of facilities.